Things to check
1 Petcock valve is open
2 Fuel is traveling through the fuel filter
3 Carb bowl is full of fuel
4 No gas leaks in the line from tank to carb
5 No air leaks. The most common air leak places:
- Carb/intake connection
- Intake/Intake manifold connection
- Head gasket
- Exhaust manifold/pipe connection
6 Check clutch cable. Does it pull the clutch arm completely back when pulled and move it completely forward when released? Here is a video
on setting up the clutch cable
7 When you release the clutch handle (engage the clutch) will it pump the piston and create compression as you spin the back wheel? When you pull the clutch handle in does the back wheel spin freely without pumping the piston? If both of these 2 things are not happening you will probably have to loosen or tighten the clutch plate. Also, make certain you don't get grease on the clutch plate or it might slip. Here is a video
on how to adjust the clutch.
8 You might check the tightness of your chain. If it is too loose it could cause the rear wheel to jerk or skid upon start. Chains will normally stretch to become slightly longer with use.
Also, while I agree with others that say a 16x1 mix is too much oil, clearly it is, however, the engine should still start with a 16x1 mix. I don't think changing your mix ratio will fix your "failure to start" issue.